Analysis of the Scattering Properties of Granular Materials

Abstract

The present study concerns diffuse reflectance spectroscopy of polymer powders and of their binary mixtures with inorganic materials. The total near-normal hemispherical spectral reflectance R of granular materials was measured in the near infrared wavelength range with a dispersive spectrophotometer. The measurement of the reflectance illustrated the influence of different parameters by taking into account (a) the morphology: powders or pellets and (b) the optical property of the material: semi-transparent, opaque or reflecting powders. The statistical treatment of the reflectance data by principal component analysis (PCA) allowed these data to be displayed in a reduced dimensionality space. As a result, the clustering of samples related to their chemical or their physical nature was carried out, giving a simpler description of the data in a new representation. The cross-correlation analysis of the reflectance values allowed similarities between absorption bands to be highlighted.